code: def test_unflatten_empty(self):
      a = {"a": 1, "b": nnx.Param(2)}
      g = [a, 3, a, nnx.Param(4)]
  
      state, static = nnx.graph_utils.graph_flatten(g)
      g = static.merge(nnx.State({}))
  
      assert g[0] is g[2]
      assert g[0]["b"].value is nnx.EMPTY
      assert g[3].value is nnx.EMPTY
  
file_path: flax/flax/experimental/nnx/tests/test_graph_utils.py
imports: import jax
  import pytest
  from flax.experimental import nnx
label_desc: Use image node_id 3 for calling the TestGraphUtils obj's underlying member method code with example usage: obj.test_unflatten_empty() without return types